Dual filter system for filtering of injector fluids

ABSTRACT

A filtering system used on a meat injection machine that injects pickling into meat products. The filter consists of a tank and a first and second rotary filter. The first rotary filter uses a wedge wire wound cylinder and augers having flutes that rotate to catch and push away solid particles toward the second filter. The second filter then uses more wedge wire in a whirlpool effect to ensure all solid materials and foam are in the outside of the filter. Injector fluid is then taken from the center of the inside volume of the second filter to be used in injection needles.

BACKGROUND OF THE INVENTION

During mechanical injection of meat products, pickling solution isinjected into the meat through a multitude of hollow needles, which arerepeatedly inserted into the meat to achieve a predetermined percentageaddition of solution. Excess solution is collected in a tray beneath theproduct for use after filtration to remove meat particles.

Currently available filter systems usually consist of a wedge wire drum,which rotates slowly. The recovered solution runs over the outside ofthe drum causing liquids to pass between the wires into a tank while thesolid particles are scraped off the outside of the drum as it rotates.The solution is then filtered through static filter screens before beingpumped back to the needles.

Often some solution is transferred with the meat particles still in thesolution. Furthermore, when filtration is not completely effective inremoving particles from the injection pickle solution, the particles endup in the pickle solution that returns to the needles. This particlematter in the solution can cause clogging which has an adverse effect onthe percentage injection rate. In addition, filters, particularly staticscreens, are prone to becoming clogged by the particles remaining in thesolution. This causes the need for repeated cleaning to reduce pumpstarvation, loss in injection pressure, and injection percentagevariation.

Cleaning of static filters without cleaning the whole system can allowsolid matter to pass through the filter and clog the system further downstream. Thus, it is a primary object of the present invention to providea filtering system for the filtering of injector fluids that improvesupon the state of the art.

Another object of the present invention is to provide a filter systemthat uses the height of flutes on an auger to retain fluid while stilltransporting solid materials to the end of the filter.

A further object of the present invention is to provide a filteringsystem that allows a fluid surface of liquid to be continually strainedof foam.

Yet a further object of the present invention is to improve theeffectiveness of a filtration system.

A further object of the present invention is to provide a filtrationsystem that can be used in filtration applications other than ininjection of meat products.

And still yet a further object of the present invention is to provide afilter that can be back-flushed while the machine is running.

These and other objects, feature, or advantages of the present inventionwill be apparent from the specification and claims.

SUMMARY OF THE INVENTION

The present invention provides a filtering system that has a filter tankand a first rotary filter consisting of a filtering cylinder with aninternal auger. In the application of the invention, both the filteringcylinder and the internal auger rotate together. The filter systemfurther comprises a substantially enclosed second rotary filter thatreceives solid particles filtered from the first rotary filter. Ascraper then removes the solid particles from the outside surface of thesecondary filter and a pipe takes the filtered liquid from the inside ofthe secondary filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a meat injection machine.

FIG. 2 is a side view of the filtration system of the meat injectionmachine.

FIG. 3 is a sectional view of the filtering system of the meat injectionmachine taken from line 4-4 of FIG. 2.

FIG. 4 shows an enlarged side view of the filter system of the meatinjection machine showing the scraper.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The term fluid, pickle fluid, and liquid are used interchangeablythroughout this disclosure and all represent the liquid portion of aliquid and solid suspension. Solid, solid particles, solid material, andmeat particles are also used interchangeably throughout this disclosureand represent the solid portion within the liquid of the solidsuspension. The terms pickle injection, injector fluid, pickle solution,and suspension are used interchangeably throughout this disclosure andall represent a liquid and solid suspension or mixture.

As can be seen in FIG. 1, the filtration system of the current inventioncan be found in meat injection machine 10. Generally the filter systemhas a first rotary filter 12, a second rotary filter 14, a tank 16, anda pump 18 that receives the filtered pickle injection from the tank 16and transports the pickle injection to the injector needles 20. Theinjector needles 20 are protected by head cover 22 and inject meatproduct 24 with the filtered pickle injection.

FIGS. 2-4 show the filtering system of the meat injection machine 10.The filtering system has a chute 26 that brings an unfiltered picklesolution into the first rotary filter 12. The first rotary filter 12consists of a wedge wire wound cylinder 28 having an auger 30. The auger30 is attached to an end plate 31 that has a central opening 33 thatallows the chute 26 to protrude there through and bayonet slots 32receive the auger 30 so that the auger 30 fits snuggly within thecylinder 12 and can rotate therewith. Cylinder 28 and auger 30 rotatetogether and are releasably attached by the quick-release bayonetconnection.

Preferably cylinder 28 has a wedge shaped wire with a flat edge on theinside and a uniform gap between wires of 0.5 mm (0.02 inches). Fordifferent applications, wires of different sizes and dimensions areused. For example, for optimizing the filtration process the gap betweenwires is varied. In another application the cylinder 28 is made ofmaterial that has holes instead of wedged wire. Also, auger 30 is madewith a uniform pitch spiral or a variable pitch depending on theapplication. Auger 30 also has flutes (not shown in drawings) that areable to retain fluid while still transporting solid material to the endof the cylinder 28, and can be of a height that varies along its lengthto optimize the filtration of liquid through the filtering cylinder 28or of a uniform height along its length. The Auger can also have uniformpitch along its length or variable pitch along its length to optimizethe filtration of liquid through the filtering cylinder.

A gear 34 is fixed to the second end 35 of first rotary filter 12 and ismeshed with a pinion wheel 36 on shaft 38 which is connected to themotor 40 on the meat injection machine 10. In operation the motorrotates the shaft 38 of pinion 36 causing the gear 34 to rotate.

The secondary filter 14 is comprised of a wedge wire wound cylinder 42having an outer surface 45, a plate 44 that is part of the sidewall ofthe tank 16 at one end, and a gear 43 at the opposite end that form aninterior chamber 53 that is partially submerged in tank 16. Gear 43 isoperably connected to pinion wheel 36 so that the pinion wheel 36operatively rotates both the first rotary filter 12 and the secondrotary filter 14. Operably attached to the tank 16 is a scraper 48 usedto clean the cylinder 42. Scraper 48 can be a mechanical blade or an airknife. Also attached to the tank 16 is a container 50 for receivingmaterial removed from cylinder 42.

A pipe 52 extends outwardly from the plate 44 and is in communicationwith the interior chamber 53 of the secondary filter 14. The pipe 52provides an outlet for the filtered liquid in the interior chamber 53 ofthe secondary filter 14. Pipe 52 is operably connected to the pump 18 totransport filtered liquid from the interior chamber 53 of the secondaryfilter 14 to the injection needles 20.

In operation, a pickle fluid having meat particles falls from chute 26into cylinder 28. Liquid passes through the gaps between the wires ofcylinder 28 and drains into tank 16, while the solid particles aretransported along the length of cylinder 28 by the rotating auger 30. Inone embodiment the auger 30 and filtering cylinder 28 are rotated atdifferent speeds. The solid particles with some excess liquid then fallsfrom the second end 35 of the cylinder 28 onto the outer surface 45 ofthe second rotary filter 14. As the cylinder 42 rotates, solid particlescollect on the wedge wire and are transported to the scraper 48 wherethe solid particles are deposited into container 50.

As pump 18 draws liquid via pipe 52 from the interior chamber 53 ofsecondary rotating filter 14 it generates a negative pressure ininterior chamber 53. This draws fluid from tank 16 into interior chamber53 through cylinder 42. Any remaining solids in this fluid are depositedon the outer surface 45 of rotating cylinder 42, which transports themto scraper 48 as it rotates.

Any foam (protein and fat) floating on the surface of fluid in tank 16is lifted off as cylinder 42 rotates and it too is transported toscraper 48 which removes it and deposits it into container 50. Then pipe52 transports the filtered liquid from the interior chamber 53 of thecylinder 42 to the injection needles 20. As the pipe 52 transportsfiltered liquid from the interior chamber 53 of cylinder 42 extraunfiltered liquid is introduced to the tank 16 via the first rotarycylinder 12, replenishing the fluid lost in the system.

In one application the filters are backwashed during the operation ofthe filtering system. To backwash the first rotary filter 12, an airknife is installed close to the first rotary filter 12. Similarly, thesecond rotary filter 14 may be backwashed by placing a nozzle within thesecond rotary filter. Fluid is pumped at high pressure at the interiorof the second rotary filter 14 to back flush it and force particles thatmay be clogging it back into the tank 16.

Thus, a filtering system for the filtering of injector fluids thatimproves upon the state of the art is disclosed. The filtering systemeliminates the need for static filters by using two rotating cylindricalfilters. The system also creates a whirlpool effect that allows foam tobe continually strained from the surface of the liquid in the tank. Thissystem may be used in a meat pickling process or any other processwherein solid particles are to be filtered out of a liquid. Furthermore,the filters in this system may be back-flushed while the machine inoperation. It will be appreciated by those skilled in the art that othervarious modifications could be made to the device without the partingfrom the spirit in scope of this invention. All such modifications andchanges fall within the scope of the claims and are intended to becovered thereby.

1. A filtering system for filtering solid waste comprising: a firstrotary filter having a first elongated filtering cylinder with porousoutside surface, a first and second end and an internal auger; a tankoperably connected to the first rotary filter and adapted to receiveliquid from the first rotary filter; and a second rotary filter, havinga second elongated filtering cylinder with a porous outside surface, anda first and second end forming an interior chamber, partially disposedwithin the tank and adapted to receive solid waste from the first rotaryfilter.
 2. The filtering system of claim 1 further comprising a meansfor removing solid waste from the outside surface of the second rotaryfilter operably connected to the tank.
 3. The filtering system of claim1 further comprising a pipe in communication with the interior chamberof the second elongated filtering cylinder.
 4. The filtering system ofclaim 3 further comprising injection means fluidly connected to thepipe.
 5. The filtering system of claim 2 wherein the means for removingsolid waste is a scraper.
 6. The filtering system of claim 2 wherein themeans for remaining solid waste is an air knife.
 7. The filter system ofclaim 1 further comprising a backwashing means for backwashing the firstfilter while the system is in operation.
 8. The filter system of claim 1further comprising a backwashing means for backwashing the second filterwhile the system is in operation.
 9. The filter of claim 1 wherein theauger and the first elongated filtering cylinder are operably connectedwith a bayonet connection.
 10. The filtering system of claim 1 furthercomprising a first gear operably connected to the first filter and asecond gear operably connected to the second filter such that that thefirst and second gears are driven from a common drive.
 11. The filteringsystem of claim 10 wherein the first gear and the second gear are drivenat different speeds.
 12. The filtering system of claim 1 wherein thefirst elongated filtering cylinder of the first rotary filter is made ofwedge shaped wires wound to leave a consistent gap to allow liquid topass, but prevent the passing of solids of a predetermined size.
 13. Thefiltering system of claim 1 wherein the first elongated filteringcylinder of the first rotary filter is made of wedge shaped wires woundto leave a gap between wires that varies in a predefined manner alongits length to progressively allow increasing sizes of solids to passthrough.
 14. The filtering system of claim 1 wherein the auger of thefirst rotary filter is of uniform height along its length.
 15. Thefiltering system of claim 1 wherein the auger of the first rotary filteris of a height that varies along its length to optimize the filtrationof liquid through the filtering cylinder.
 16. The filtering system ofclaim 1 wherein the auger of the first rotary filter has a uniform pitchalong its length.
 17. The filtering system of claim 1 wherein the augerof the first rotary filter has a variable pitch along its length tooptimize the filtration of liquid through the filtering cylinder. 18.The filtering system of claim 1 wherein the auger and first filteringcylinder are rotated at different speeds.
 19. A method of filteringsolids from a suspension of liquids and solids comprising steps of:introducing a solid and liquid solution into a first rotary filterhaving a first elongated filtering cylinder and an internal auger;allowing the liquid to pass through a porous outer cylinder while thesolids are transferred by the auger to the second end of the filter;dropping the solids onto the exterior of a second rotary filter having asecond elongated filtering cylinder with first and second ends, a porousoutside surface, and partially disposed in a tank; rotating the secondrotary filter so that the solids are transferred to a scraper while anyremaining fluid, together with fluid from the tank passes through theporous outer surface from where it can be pumped out of the filteringsystem.
 20. The method of claim 19 wherein the second rotary filter alsoremoves foam from the surface of the liquid in the tank.
 21. The methodof claim 19 wherein fluid is pumped at high pressure at the inside ofthe surface of the second rotary filter to back flush it and forceparticles that may be clogging it back into the tank.